The present invention is directed to a battery apparatus, and more particularly a battery apparatus having means for identifying individual batteries, a real-time clock, and means for authenticating batteries.
Rechargeable batteries have some great advantages when compared with regular, disposable batteries. For example, rechargeable batteries have a lower lifetime cost for most applications.
However, rechargeable batteries also have some disadvantages. For example, every time a rechargeable battery is used or recharged, a substantial transport of material takes place in the battery. In practice, it is impossible to design a battery so that the distribution of material involved will be unchanged over time, though such a design would be desirable. An increasing number of charging cycles will result in an uneven distribution of material inside the battery with a rising risk of malfunction, for example, an internal short-circuit of the battery, as a result thereof. It is of great importance to minimize the risk of malfunction of a battery, because every malfunction means a potential risk for people and material in vicinity of the battery.
Today, battery manufacturers try to minimize the risks by providing over-pressure vents, explosion-safe encapsulation, etc. One way to minimize the risk of malfunction is to allow only a limited number or charging cycles during the lifetime of a rechargeable battery. In other words, the life-time of the battery may be defined by a number of charging cycles or a maximum charging time. When using this type of battery, it would be of value if environmental factors as well, for example, heat, could be used for the calculation of the acceptable number of charging cycles.
U.S. Pat. No. 5,136,620 to Eaves discloses an electronic counting device for counting the charge cycles accumulated on a battery. However, the counting device consists of a display by which a counted value is output to the user. The user must know what the count means in terms of the battery life; there is no mechanism by which the application circuit or recharging device to which the battery is connected receives this information.
Other prior art combinations of batteries and charging circuits have had either a simple way to identify a battery as a member of a certain class or family (U.S. Pat. No. 5,184,059 to Patino et al. and U.S. Pat. No. 5,200,686 to Lee), or a complex arrangement inside the battery pack to secure that this battery pack individual will be treated the best way (U.S. Pat. No. 4,553,081 to Koenck, U.S. Pat. No. 5,057,083 to Sokira, U.S. Pat. No. 4,965,738 to Bauer et al., and U.S. Pat. No. 4,289,836 to Lemelson). However, these devices do not provide a signature for every battery pack which is easy to produce and easy to recognize with a high degree of probability, to make it possible for the charger and/or the battery-powered apparatus to recognize a single individual battery.
Another problem found in existing rechargeable batteries results from the marketing of batteries made by unauthorized manufacturers. In particular, manufacturers of portable equipment which is supplied with power by rechargeable batteries want to supply the market with their own batteries. This is a result of both commercial and technical considerations. If a customer buys a battery from an unauthorized manufacturer, there may be a safety risk because the batteries are not compatible with the original battery charger.
For example, U.S. Pat. No. 4,593,409 to Miller discloses a warning and protection circuit arrangement suitable for use in conjunction with a two-way portable transceiver having a removable battery pack/antenna which includes a battery enclosure containing an antenna structure. A circuit is enclosed inside the battery enclosure for providing information indicative of certain predetermined parameters of the antenna or the battery. This information may be used by the transceiver to provide the user with an alert in the event an inappropriate battery pack/antenna is being used. However, this requires the provision of a separate circuit thus increasing the size and cost of the battery pack.
A cellular telephone including a battery time monitor having a real time clock is disclosed in U.S. Pat. No. 5,248,929 to Burke. This patent discloses use of the battery time monitor which provides a user with a visual feedback as to the amount of time remaining for operation of the cellular telephone so that the user may determine how long the next call can last before the battery is discharged. However, this requires a separate circuit within the cellular telephone to monitor the battery. Additionally, because the clock is provided in the cellular telephone circuit, if the battery becomes totally discharged, the real time clock may lose its ability to keep time accurately.